Anemia Discussion

Overview

• Talk focused on types of microcytic anemia:
  • Iron Deficiency Anemia
  • Anemia of Chronic Disease
  • Thalassemia (to be discussed later)

Hemoglobin Structure

• Components:
  • Heme: consists of iron and protoporphyrin
  • Globin: protein part of hemoglobin
• Function:
  • Each hemoglobin molecule can bind four oxygen molecules
  • Binds oxygen at the heme portion, specifically at the iron in the ferrous (Fe2+) state
• Appearance:
  • Resembles a butterfly with four subunits:
    • 4 protein (globin) subunits
    • 4 non-protein (heme) groups

Synthesis

• Heme is synthesized in the mitochondria and cytosol of immature red blood cells (RBCs)
• Globin is synthesized by ribosomes

Subunits

• Two main subunits:
  • Alpha (α) subunit
  • Beta (β) subunit
• Normal adult hemoglobin structure:
  • 2 alpha subunits and 2 beta subunits

Heme Group

• Contains protoporphyrin and iron in the ferrous state (Fe2+)
• Ferric (Fe3+) state results in methemoglobin which cannot carry oxygen

Types of Hemoglobin

• Adult Hemoglobin (HbA):

  • 95% of total adult hemoglobin
  • Structure: α2β2 (2 alpha and 2 beta subunits)

• Fetal Hemoglobin (HbF):

  • Present in adults at about 1%
  • Structure: α2γ2 (2 alpha and 2 gamma subunits)

• Hemoglobin A2 (HbA2):

  • Forms 1.5% to 3% of adult hemoglobin
  • Structure: α2δ2 (2 alpha and 2 delta subunits)

Conclusion

• These are foundational concepts for understanding thalassemia, to be discussed in future content.

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